I am currently trying to understand the Sine Sweep Method for taking acoustic measurements.

I am following this paper: https://www.thinksrs.com/downloads/pdfs/applicationnotes/SR1_SweptSine.pdf

I am at a point where I can output the sweep stimulus, record the measurement, and compare the two audio files produced.

I am more confused about how to deal with the two signals I have. I would like to be able to get an impulse response from my reference and measurement. I believe this is achieved through circular cross correlation. (division of the two signals in the frequency domain, and then perform inverse FFT).

However, currently there is a time delay for each frequency (so it does not act as an impulse). I need to manually subtract the time taken for each frequency, however, how do I achieve this. The paper mentions 'the group delay at each frequency must be subtracted, however I am confused as to how to achieve this.

Currently I am taking a Wavelet Transform on the measurement signal to give me detailed frequency analysis (more frequency resolution in the lower frequencies, and taking an average of the entire measurement time). Similarly I would like to be able to extract the phase different between the two signals, however I believe I need to sort out this time delay first, for this to be applicable.

Once I have found a way to give me an impulse, I can choose my phase delay reference relative to the impulse time.

Please can someone guide me towards the right direction?


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